The present invention relates to a liquid crystal display apparatus, in particular, to a liquid crystal display apparatus provided with an effective function for reflective color displaying.
A conventional reflective color liquid crystal display apparatus, which comprises a reflector provided on many micro-protrusions formed of resin, is disclosed in JP-A-4-243226 (1992). A color filter for reflective color liquid crystal display apparatus is disclosed in JP-A-6-230364 (1994) and others. The color filter does not make any trouble in driving liquid crystal, even if an optical reflector composing a reflector causes an electrical short circuit with transparent electrodes via a defect of color filter, by patterning the reflector to a shape approximately as same as the shape of the color filter.
In accordance with the prior art, a reflector comprising many fine protrusion-depression reflecting planes, whereon circular protrusions or depressions are arranged irregularly so as not to generate optical interference, is disclosed.
Furthermore, as disclosed in JP-A-10-177106 (1998), a liquid crystal display apparatus; wherein liquid crystal element comprises a reflector, which is made to collect incident light in a specified direction by forming circular protrusions or depressions having unsymmetrical distribution of slope angles in their cross section shape; has been proposed.
In accordance with the prior art described above, any black matrix becomes unnecessary, because the liquid crystal driving does not cause any trouble, even if an optical reflecting film composing a reflector causes an electrical short circuit with transparent electrodes via a defect of color filter, by patterning the reflector to a shape approximately as same as the shape of the color filter, and unnecessary reflection light from unopened portion can be prevented. However, the color filter for reflective color liquid crystal display apparatus had such a problem that contrast was decreased with an element structure having no black matrix layer depending on display mode (for instance, normally open mode), because the color filter for reflective color liquid crystal display apparatus must have spectral characteristics utilizing positively the light in a certain wavelength region, which should be shielded naturally.
Because a liquid crystal layer having an uniform thickness could not be formed with the composition of the prior art described above, wherein only a color filter layer was formed on a surface-roughened reflector, the color filter had additionally such problem that a quality of display (brightness and contrast) was decreased.
In accordance with the prior art, if a leveling layer was provided onto the color filter layer for forming a liquid crystal layer having an uniform thickness, a problem such as decreasing the brightness and others were generated.
The prior art had a problem that display was dark, because, in order to prevent coloring caused by optical interference by arranging circular protrusions or depressions irregularly in a region corresponding to pixel electrode portions, the number of protrusions or depressions, which were reflecting elements for controlling incident light, was decreased significantly from a case when the protrusions or depressions were arranged in a closest packing manner.
In accordance with the prior art, reflected light was collected in a specified direction by making the slope angle distribution of the circular protrusions or depressions unsymmetrical. Therefore, there was a problem such as difficulty in controlling the shape of the fine protrusion or depression, because the manufacturing process became complex.
Furthermore, in accordance with the prior art, fine circular protrusions or depressions were formed by a photolithography method. Therefore, there was a problem such as a high cost, because the manufacturing process was complex, and the number of manufacturing steps was large.
The object of the present invention is to provide a liquid crystal display apparatus comprising a reflector having preferable reflecting characteristics by solving the above described problems, and to provide a manufacturing method thereof.
As a first means for achieving the above object, the reflective color liquid crystal display apparatus of the present invention uses the following liquid crystal display element:
The liquid crystal display element comprises an electrode substrate: wherein a reflector composed of a metal such as aluminum, silver, and others, is formed on many fine protrusions and depressions formed with a resin, wherein a black pigment having light shielding function is dispersed, on a glass substrate corresponding to apertures: color filters of red, green, and blue having leveling function are formed on the reflector; and transparent electrodes and alignment layer are formed on the color filters: and another electrode substrate: wherein transparent electrodes and alignment layer are formed on a glass substrate: the liquid crystal display element is manufactured by matching the electrode substrates via a spacing material for defining thickness of the liquid crystal so that each of the alignment layers are faced each other, filling liquid crystal into the interval between the electrode substrates by any method such as vacuum filling method and the like, and sealing the interval.
As a second means for achieving the above object, the reflective color liquid crystal display apparatus of the present invention is a reflective color liquid crystal display apparatus comprising a reflector composed by laminating a polymer layer having protrusions and depressions and a reflective layer onto a glass substrate: the reflector comprises the polymer layer, whereon fine protrusion-depression planes are formed by the following method and the like in order to achieve the above object:
1) string shaped protrusions having smooth curves, or string shaped depressions are arranged continuously and alternately,
2) string shaped protrusions having smooth curve are arranged continuously, and
3) string shaped depressions having smooth curve are arranged continuously.
In accordance with the reflector of the reflective liquid crystal display apparatus of the present invention, fine protrusion-depression planes are formed on the polymer layer by arranging the string shaped protrusions or the string shaped depressions in a manner that the slope angle distribution of the cross section shapes of the depressions and depressions in a direction at a right angle to the longitudinal direction is approximately symmetrical from right and left, and total lengths of the respective string shaped protrusions or string shaped depressions in respective directions are approximately equal.
In accordance with the reflector of the reflective liquid crystal display apparatus of the present invention, fine protrusion-depression planes are formed on the polymer layer by arranging the string shaped protrusions or the string shaped depressions in a manner that the slope angle distribution of the cross section shapes of the depressions and depressions in a direction at a right angle to the longitudinal direction is approximately symmetrical from right and left, and total lengths of the respective string shaped protrusions or string shaped depressions in respective directions differ each other.
The reflective liquid crystal display apparatus of the present invention is featured in having an element structure; wherein an electrode substrate comprising a polymer layer, which comprises the fine protrusion-depression planes composed of the string shaped protrusions and string shaped depressions, a reflective layer, an insulating layer, transparent electrodes, and an alignment layer laminated on a glass substrate; and another electrode substrate comprising a black matrix layer, color filters, a leveling layer, transparent electrodes, and an alignment layer are laminated on a glass substrate; are arranged so that the transparent electrodes of the above respective electrode substrates are faced each other via the liquid crystal.
The reflective liquid crystal display apparatus of the present invention is featured in having an element structure; wherein an electrode substrate comprising polymer layers, wherein black pigment and the like is dispersed, comprising fine protrusion-depression planes composed of the string shaped protrusions and string shaped depressions, rectangular reflective layers arranged only at portions corresponding to the pixels, color filters, leveling layers, transparent electrodes, and alignment layers laminated on a glass substrate; and another electrode substrate comprising transparent electrodes, and alignment layers are laminated on a glass substrate; are arranged so that the transparent electrodes of the above respective electrode substrates are faced each other via the liquid crystal.
The reflective liquid crystal display apparatus of the present invention is featured in forming the protrusion-depression pattern composed of the protrusions or depressions by a simulation method of phase separation pattern generation by spinodal decomposition, and the protrusion-depression pattern is used as a black matrix pattern for a photo mask used in forming the polymer layer, or a master pattern for protrusion-depression pattern formed in a transcription die.
In accordance with the reflective liquid crystal display apparatus of the present invention, the simulation method for pattern generation by spinodal decomposition is a numerical simulation using:
1) Cahn-Hilliard-Cook equation,
2) Time dependent Ginzburg-Landau equation,
3) Cell-Dynamical-System equation, and others.
In accordance with the reflective liquid crystal display apparatus of the present invention, a pattern of the black matrix portion or a pattern of transparent portion for the photo mask used in forming the reflector is any of the pattern generated by simulation of the spinodal decomposition, or a pattern obtained by image processing of the pattern generated by simulation of the spinodal decomposition and taken into a computer and the like.
In accordance with the reflective liquid crystal display apparatus of the present invention, the pattern generated by the simulation method is any one of pattern indicating reflecting characteristics uniform to all directions, or pattern indicating such reflecting characteristics that incident light is collected in a specified direction.
In accordance with the reflective liquid crystal display apparatus of the present invention, following liquid crystal display elements are used: the liquid crystal display element comprises; a reflective electrode substrate composed by laminating a reflector formed on a polymer layer comprising smooth protrusion-depression planes composed of string shaped pattern, which can be arranged in a closest packing manner, an insulating layer, plural transparent electrodes, an alignment layer on one side of a glass substrate; a color filter substrate composed by laminating a black matrix layer, color filters, a leveling layer, plural transparent electrodes, and an alignment layer on one side of another glass substrate; and liquid crystal filled in an interval between the reflective electrode substrate and the color filter substrate.
A method for manufacturing the reflective liquid crystal display apparatus of the present invention comprises: a method of forming a reflection electrode substrate comprising the steps of; applying a photosensitive resin onto a glass substrate, forming a polymer layer comprising smooth protrusion-depression planes composed of string shaped protrusions and string shaped depressions using a transcription casting roll, or a template, and the like having the protrusions and depressions satisfying the above conditions; forming a reflective layer onto the polymer layer, forming an insulating layer onto the reflective layer, forming transparent electrodes onto the insulating layer, and forming an alignment layer onto the transparent electrodes: a method of forming color fiter substrate comprising the steps of; forming a black matrix layer onto one side of the other glass substrate, forming color filters onto the black matrix layer, forming a leveling layer onto the color filter, forming transparent electrodes onto the leveling layer, and forming an alignment layer onto the transparent electrodes: and a step of filling liquid crystal into an interval between the reflection electrode substrate and the color filter substrate, and sealing the interval.
Furthermore, the method for manufacturing the reflective liquid crystal display apparatus of the present invention is a method for manufacturing a reflective liquid crystal display apparatus comprising a reflector composed of a reflector formed on a glass substrate, whereon a polymer layer comprising smooth protrusion-depression planes satisfying the following conditions have been formed;
1)string shaped pattern having smooth curves,
2) a pattern wherein the string shaped protrusions and string shaped depressions are arranged so that the protrusions and depressions are arranged continuously, or the protrusions or the depressions are arranged continuously,
3) a pattern wherein sums of total length components in any directions of the protrusions and that of the depressions are approximately equal, or sums of total length components in respective directions of the protrusions and that of the depressions are different each other.
The method for manufacturing a reflective liquid crystal display apparatus comprises a method of manufacturing a liquid crystal display element, which comprises a method of forming a reflection electrode substrate comprising the steps of; applying a photosensitive resin onto a side of the glass substrate composing the reflector to form a polymer layer comprising smooth protrusion-depression planes by patterning the polymer layer with a transcription casting roll, or a template, and the like, whereon the pattern is formed to satisfy the above conditions; shaping the polymer layer comprising the protrusion-depression planes to smooth protrusion-depression planes by irradiating light or heat treating the substrate; forming a reflective layer onto the polymer layer comprising the smooth protrusion-depression planes; forming a leveling layer onto the reflective layer, forming plural transparent electrodes onto the leveling layer, and forming an alignment layer onto the transparent electrodes: a method of forming a color filter substrate comprising the steps of; forming a black matrix layer onto another glass substrate, forming color layers onto the black matrix layer, forming a leveling layer onto the coloring layers, forming plural transparent electrodes onto the leveling layer, and forming an alignment layer onto the transparent electrodes: and a method comprising the steps of facing respective of alignment layer each other, and a step of filling liquid crystal into an interval between the reflection electrode substrate and the color filter substrate, and sealing the interval. The method for manufacturing a reflective liquid crystal display apparatus further comprises the steps of adhering a designated phase plate and polarizer on the plane of the glass substrate other than the plane whereon the color filters of the liquid crystal display element is formed, connecting tape carrier package (hereinafter called TCP), whereon an IC for driving the liquid crystal is mounted, and an external circuit for driving to the liquid crystal display element, and assembling the liquid crystal display element into a frame, case, and the like.
Another method for manufacturing a reflective liquid crystal display apparatus is a method for manufacturing a reflective liquid crystal display apparatus having a reflector, wherein a reflector is formed on a glass substrate having many fine protrusions or depressions formed thereon. The method comprises a method of manufacturing a liquid crystal display element. The method of manufacturing a liquid crystal display element comprises: a method of forming a reflection electrode substrate comprising the steps of; applying a photosensitive resin onto a side of the glass substrate composing the reflector, subsequently forming a polymer layer comprising smooth protrusion-depression planes, whereon string shaped protrusions and string shaped depressions are arranged continuously and alternately, by patterning the polymer layer by heat treatment after exposing and developing the photosensitive resin via a light shielding means, wherein the pattern is formed using a simulation of spinodal decomposition so that the string shaped pattern comprises smooth curves having an uniform width and a designated length component in black matrix region or transparent region, and sum of the length components in the black matrix region or transparent region become approximately equal each other in respective directions; forming a reflective film on the polymer layer having the protrusion-depression planes, forming a leveling layer on the reflective layer, and forming plural transparent electrodes on the leveling layer: a method of forming a color filter substrate comprising the steps of; forming a black matrix layer onto another glass substrate, forming color filters onto the black matrix layer, forming a leveling layer onto the color filters, and forming plural transparent electrodes onto the leveling layer: and a method comprising the steps of facing respective of transparent electrodes each other, and a step of filling liquid crystal into an interval between the reflection electrode substrate and the color filter substrate, and sealing the interval. The method for manufacturing a reflective liquid crystal display apparatus is completed by adding further the steps of adhering a designated phase plate and polarizer on the plane of the glass substrate other than the plane whereon the color filters of the liquid crystal display element are formed, connecting TCP, whereon an IC for driving the liquid crystal is mounted, and an external driving circuit to the liquid crystal display element, and assembling the liquid crystal display element into a frame, case, and the like.